Dr. Alexander Rae-Grant, who treats people with Alzheimer’s disease at Cleveland Clinic, said the results are encouraging from a research standpoint.

"It's not for here and now, but it may give us a pathway to go in the next step to try and change the course of this disease which affects millions and millions of people," said Rae-Grant.

Researchers in this multi-center trial looked at over 400 patients with mild-to-moderate Alzheimer’s disease for 73 weeks in two phase-two studies, which are designed to test the effectiveness and safety of new drugs.

Some patients were given a high dose of the drug, Crenezumab, intravenously every four weeks.

Others were given a low dose injection of the drug under the skin every other week. And the rest were given a placebo.

The goal of the research was to delay cognitive and functional decline in the patients.

The drug did not meet the goal completely, but in milder forms of the disease, the high-dose intravenous form of the drug did show evidence of slowing the decline of cognitive abilities.

“I think it's promising in that we're really looking for a signal to say that we're changing the disease course and it may be some kind of signal, it is not the final answer. You know, it's not the endpoint but the beginning," Rae-Grant said.

According to the Alzheimer’s association, an estimated 5.5 million people in the United States have Alzheimer’s disease.

Some famous people with Alzheimer's disease

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OTD July 16 - William Asher

2012: William Asher, one of the most prolific early television directors, known especially for his work on "I Love Lucy" and "Bewitched," dies from complications of Alzheimer's disease at age 90 in Palm Desert, California. Asher directed more than 100 episodes of "I Love Lucy" and also produced "Bewitched" during its entire eight-year run. At that time, he was married to the show's star Elizabeth Montgomery, although they divorced soon after the cancellation of the series in 1972. He also directed episodes of "Make Room for Daddy," "The Twilight Zone," "The Patty Duke Show," "Gidget," "The Dukes of Hazzard" and "Alice," and several movies, including "Muscle Beach Party," "Bikini Beach" and "Beach Blanket Bingo."